"You have moved the tables and searched behind the sofas," I suggested.
"Not an inch of the floor has escaped our attention, madam."
My eyes fell on the register, which my skirts half covered. It was closed; I stooped and opened it. A square box of tin was visible below, at the bottom of which I perceived the round head of a broken hat-pin.
Never in my life had I felt as I did at that minute. Rising up, I pointed at the register and let some of my triumph become apparent; but not all, for I was by no means sure at that moment, nor am I by any means sure now, that he had not made the discovery before I did and was simply testing my pretensions.
However that may be, he came forward quickly and after some little effort drew out the broken pin and examined it curiously.
"I should say that this is what we want," he declared, and from that moment on showed me a suitable deference.
"I account for its being there in this way," I argued. "The room was dark; for whether he lighted it or not to commit his crime, he certainly did not leave it lighted long. Coming out, his foot came in contact with the iron of the register and he was struck by a sudden thought. He had not dared to leave the head of the pin lying on the floor, for he hoped that he had covered up his crime by pulling the heavy cabinet over upon his victim; nor did he wish to carry away such a memento of his cruel deed. So he dropped it down the register, where he doubtless expected it would fall into the furnace pipes out of sight. But the tin box retained it. Is not that plausible, sir?"
"I could not have reasoned better myself, madam. We shall have you on the force, yet."
But at the familiarity shown by this suggestion, I bridled angrily. "I am Miss Butterworth," was my sharp retort, "and any interest I may take in this matter is due to my sense of justice."
Seeing that he had offended me, the astute detective turned the conversation back to business.